Petroleum

Photo by: O.V.D.

Petroleum is a naturally occurring liquid oil normally found in deposits
beneath the surface of the earth. It is a type of oil composed of rock
minerals, making it different from other kinds of oils that come from
plants and animals (such as vegetable oil, animal fat, or essential oils).
The word petroleum comes from the Latin words
petra
(rock) and
oleum
(oil), and so literally means
rock oil.
Despite this, petroleum is an organic compound, formed from the remains
of microorganisms living millions of years ago. It is one of the three
main fossil fuels, along with coal and natural gas.

Petroleum Economy

Petroleum, like all fossil fuels, primarily consists of a complex mixture
of molecules called
hydrocarbons
(molecules containing both hydrogen and carbon). When it comes out of the
ground, it is known as
crude oil,
and it may have various gases, solids, and trace minerals mixed in with
it. Through refinement processes, a variety of consumer products can be
made from petroleum. Most of these are fuels: gasoline, jet fuel, diesel
fuel, kerosene, and propane are common examples. It is also used to make
asphalt and lubricant grease, and it is a raw material for synthetic
chemicals. Chemicals and materials derived from petroleum products include
plastics, pesticides, fertilizers, paints, solvents, refrigerants,
cleaning fluids, detergents, antifreeze, and synthetic fibers.

The modern petroleum industry began in 1859 in Pennsylvania, when a man
named Edwin L. Drake constructed the first oil well, a facility for
extracting petroleum from natural deposits. Since then, petroleum has
become a valuable commodity in industrialized parts of the world, and oil
companies actively search for petroleum deposits and build large
oilextraction facilities. Several deposits exist in the United States.
However, around 1960 oil production in the country began to decline as oil
in the deposits was being used up and fewer new deposits were being
discovered. Demand for petroleum products continued to increase, and as a
result the United States came to rely more and more on oil imported from
other countries. In 2001 the amount of petroleum extracted from deposits
in the United States was estimated to be only one-third of the amount
demanded by U.S. consumers. A similar pattern exists in other
industrialized countries, and some, like Japan and Germany, import almost
all of the oil they use.

However, on a per capita basis, the consumption in these countries is
nowhere near the consumption in the United States.

The United States and Canada are unique in that, on average, an individual
in these countries consumes about twice as much petroleum product as do
individuals in most other industrialized nations. People in the United
States and Canada rely more on personal vehicles for their transportation
and tend to drive greater distances, making petroleum their major source
of energy. In the United States, about two-thirds of the petroleum
consumed is transportation fuel, and two-thirds of that (45% of the total)
is gasoline for cars and trucks. About 40 percent of the energy used in
the United States every year comes from petroleum.

Foreign Oil Dependence

Political leaders in the United States have long been gravely concerned
about the country's growing dependence on foreign oil, which in
many ways puts the country at the mercy of foreign governments, some of
them hostile to the United States. The greatest production of crude oil in
the world is in the Persian Gulf region of the Middle East, where about 65
percent of the world's known petroleum deposits are located. About
half of U.S. imports come from members of the Organization of the
Petroleum Exporting Countries (OPEC), a group of countries encompassing
the Persian Gulf and certain parts of Africa and South America. Events in
these often volatile regions can have a huge impact on oil prices in the
United States and worldwide, and because of the crucial role oil plays in
U.S. society any change in the price can precipitate uncontrollable shifts
in the country's economy (see chart "World Oil Price
1970-2000"). The most famous example of this is the Arab Oil
Embargo of 1973 to 1974, when U.S. support for Israel in a conflict in the
Middle East led to a decision by OPEC to impose steep price increases on
the sale of oil to the United States. One response by the U.S. government
has been the establishment of the Strategic Petroleum Reserve, an
emergency stockpile designed to sustain the country's oil needs for
approximately three months in the event of a complete cutoff of imports.
There is little doubt, however, that dependence on foreign oil is both a
political liability for the United States as well as a risk to national
security.

Workers using water hoses to clean oil from a beach following a
spill. (

United States Environmental Protection Agency. Reproduced by
permission.

)

Environmental Pollution

Petroleum-derived contaminants constitute one of the most prevalent
sources of environmental degradation in the industrialized world. In large
concentrations, the hydrocarbon molecules that make up crude oil and
petroleum products are highly toxic to many organisms, including humans.
Petroleum also contains trace amounts of sulfur and nitrogen compounds,
which are dangerous by themselves and can react with the environment to
produce secondary poisonous chemicals. The dominance of petroleum products
in the United States and the world economy creates the conditions for
distributing large amounts of these toxins into populated areas and
ecosystems around the globe.

Oil Spills

Perhaps the most visible source of petroleum pollution are the
catastrophic oil-tanker spills—like the 1989
Exxon Valdez
spill in Prince William Sound, Alaska—that make news headlines and
provide disheartening pictures of oilcoated shorelines and dead or oiled
birds and sea animals. These spills occur during the transportation of
crude oil from exporting to importing nations. Crude oil travels for long
distances by either ocean tanker or land pipeline, and both methods are
prone to accidents. Oil may also spill at the site where it is extracted,
as in the case of a blowout like the Ixtoc I exploratory well in 1979 (see
table "Ten Largest Oil Spills in History"). A blowout is one
of the major risks of drilling for oil. It occurs when gas trapped inside
the deposit is at such a high pressure that oil suddenly erupts out of the
drill shaft in a geyser.

Accidents with tankers, pipelines, and oil wells release massive
quantities of petroleum into land and marine ecosystems in a concentrated
form. The ecological impacts of large spills like these have only been
studied for a very

World Oil Price 1970-2000
(

World Oil Market and Price Chronologies
DOE Energy Information Administration
; originally published by the Department of Energy's Office of the
Strategic Petroleum Reserve, Analysis Division

)

few cases, and it is not possible to say which have been the most
environmentally damaging accidents in history. A large oil spill in the
open ocean may do less harm to marine organisms than a small spill near
the shore. The
Exxon Valdez
disaster created a huge ecological disaster not because of the volume of
oil spilled (eleven million gallons) but because of the amount of
shoreline affected, the sensitivity and abundance of organisms in the
area, and the physical characteristics of the Prince William Sound, which
helped to amplify the damage. The
Exxon Valdez
spill sparked the most comprehensive and costly cleanup effort ever
attempted, and called more public attention to oil accidents than ever
before. Scientific studies of the effects of oil in Prince William Sound
are ongoing, and the number of tanker accidents worldwide has decreased
significantly since the time of the Valdez spill, due to stricter
regulations and such required improvements in vessel design as double-hull
construction.

Nonpoint Sources

Spills from tankers, pipelines, and oil wells are examples of
point sources
of pollution, where the origin of the contaminants is a single
identifiable point. They also represent catastrophic releases of a large
volume of pollutants in a short period of time. But the majority of
pollution from oil is from nonpoint sources, where small amounts coming
from many different places over a long period of time add up to
large-scale effects. Seventy percent of the oil released by human activity
into oceans worldwide is a result of small spills during petroleum
consumption. These minor unreported spills can include routine discharges
of fuel from commercial vessels or leakage from recreational boats.
However, in North America, the majority of the release originates on
land. Oil tends to collect in hazardous concentrations in the stream of
wastewater coming out of cities and other populated areas. Runoff from
asphalt-covered roads and parking lots enters storm drains, streams, and
lakes and eventually travels to the ocean, affecting all of the ecosystems
through which it passes. As cities grow, more and more people use
petroleum products—lubricants, solvents, oil-based paint, and,
above all, gasoline—and these are often improperly disposed of down
drains and sewage pipes. Industrial plants also produce small, chronic
spills that aren't noticed individually, but add up over time and
enter waterways.

Taken together, land-based river and urban runoff sources constitute over
half of the petroleum pollution introduced to North American coastal
waters due to human activity, and 20 percent of the petroleum pollution
introduced to ocean waters worldwide. When wastewater from these sources
enters the marine environment it is usually by means of an estuary, an
area where freshwater from land mixes with seawater. Estuaries are
especially critical habitats for a variety of plants and animals, and are
among the ecosystems most sensitive to pollutants.

Petroleum-Contaminated Soil

Not all oil released from land sources is quickly washed away to sea,
however. Pipeline and oil-well accidents, unregulated industrial waste,
and leaking underground storage tanks can all permanently contaminate
large areas of soil, making them economically useless as well as dangerous
to the health of organisms living in and around them. Removing or treating
soil contaminated by petroleum is especially urgent because the
hydrocarbons can leach into the underlying groundwater and move into human
residential areas. The engineering field of
bioremediation
has emerged in recent decades as a response to this threat. In
bioremediation, bacteria that feed on hydrocarbons and transform them into
carbon dioxide can be applied to an affected area. Bioremediation has in
many cases made cleaning up petroleum-contaminated sites a profitable
real-estate investment for land developers.

Air Pollution

The U.S. Environmental Protection Agency (EPA) designates six criteria
pollutants for determining air quality. These are: carbon monoxide (CO),
nitrogen oxides (NO and/or NO
2
, usually referred to as NO
x
), sulfur dioxide (SO
2
), ground-level ozone (O
3
), particulate matter (including things like soot, dust, asbestos fibers,
pesticides, and metals), and lead (Pb). Petroleum-fueled vehicles,
engines, and industrial processes directly produce the vast majority of CO
and NO
x
in the atmosphere. They are also the principal source of gaseous
hydrocarbons (also called volatile organic compounds, or VOCs), which
combine with NO
x
in sunlight to create O
3
. Ozone, while important for blocking ultraviolet rays in the upper
atmosphere, is also a key component of urban smog and creates human health
problems when present in the lower atmosphere. Sulfur dioxide is a trace
component of crude oil, and can cause acid rain when released into the air
at oil refineries or petroleum power plants. Particulate matter is
directly emitted in vehicle exhaust and can also form from the reaction of
exhaust gases with water vapor and sunlight. Finally, leaded gasoline is a
huge contributor of lead to the atmosphere, and
the use of unleaded gasoline has decreased lead concentrations
dramatically. The EPA and the World Bank are working to encourage the
phaseout of leaded gasoline worldwide.

Petroleum-fueled transportation and coal-burning power plants are
considered the chief causes of global warming. Excess amounts of carbon
dioxide, methane, and NO
x
, among other gases, trap heat in the atmosphere and create the greenhouse
effect. Carbon dioxide (CO
2
) is a main constituent of petroleum fuel exhaust, even though it is not
toxic and therefore not classified as a pollutant. About one-third of the
CO
2
emitted into the atmosphere every year comes from vehicle exhaust.
Methane (NH
3
), although usually associated with natural gas, is also emitted whenever
crude oil is extracted, transported, refined, or stored.

The Future of Petroleum

The world's reliance on petroleum is expected to grow, despite
widespread environmental, economic, and political consequences. The U.S.
oil extraction industry continues to aggressively search for new oil
deposits and lobby the federal government to open up restricted areas to
drilling. The Arctic National Wildlife Refuge in Alaska has been on the
oil industry agenda for several decades, creating a long-standing
environmental controversy. Advances in oil well technology have allowed
extraction in the deep ocean beyond the continental shelf, but these have
not been enough to reverse the trend of declining production in the United
States.

There are many compelling reasons to decrease society's dependence
on petroleum for energy, and the most obvious place to begin is in the
transportation sector. Energy-efficient engines and hybrid gas/electric
cars can help to reduce some of the need for oil, providing higher gas
mileage and less demand. A variety of alternative fuels have also been
developed, such as ethanol, biodiesel (made from vegetable oil), and
hydrogen. Each of these would produce little or no exhaust pollutants or
greenhouse gases, and each derives from plentiful renewable resources. The
United States is now in fact actively researching hydrogen as a viable
alternative to gasoline, and the hydrogen fuel cell as a substitute for
the internal combustion engine.

Petroleum is a useful chemical substance for many important purposes. But
it is also a nonrenewable resource with a highly toxic composition, and it
poses significant problems when used in huge volumes throughout the
industrialized world.

Bibliography

Internet Resources

Committee on Oil in the Sea, National Research Council. (2003).
Oil in the Sea III:
Inputs, Fates, and Effects.
Washington, D.C.: The National Academies Press. Available from
http://www.nap.edu/catalog/10388.html
.

Energy Information Administration. "Official Energy Statistics from
the U.S. Government." Available from
http://www.eia.doe.gov
.

Exxon Valdez Oil Spill Trustee Council. "Restoring the Resources
Injured by the Exxon Valdez Oil Spill and Understanding Environmental
Change in the Northern Gulf of Alaska." Available from
http://www.oilspill.state.ak.us
.

OIL SEEPS

Almost half (45%) of the petroleum entering the marine environment is from
natural seeps rather than anthropogenic sources. At seeps, oil and gas
bubble out of cracks in the seabed creating special environments in which
new organisms grow. These organisms survive through chemosynthesis rather
than photosynthesis. They live in total darkness, more than four hundred
meters below sea level, but survive by feeding directly off the
hydrocarbons present in seeps or by eating carbon compounds resulting from
chemosynthetic bacterial degradation of seep oil. Since 1984
oceanographers have discovered chemosynthetic communities of clams,
mussels, tubeworms, bacterial mats, and other organisms on the seafloor of
the Gulf of Mexico. United States Department of the Interior regulations
protect these chemosynthetic communities from damage due to oil and gas
drilling activities.